Machine for finishing pistons



Sept. 15, 1953 c. G. MENARD ETAL MACHINE FOR FINISHING PISTONS 9Sheets-Sheet 1 Filed Jan. 16, 1951 nv VENTORS CLIFFORD a. MENA RD JOHNJ. He can:

Sept. 15, 1953 c. e. MENARD ET AL MACHINE FOR FINISHING PISTONS 9Sheets-Sheet 2 Filed Jan. 16, 1951 Ndxk INVENTORS CLIFFORD E. MENARDJ01?! J. Me

Sept. 15, 1953 c. G. MENARD ET AL 2,

MACHINE FOR FINISHING PISTC JNS Filed Jan. 16, 1951 9 Sheets-Sheet 3INVENTORS CLIFFORD G. MEI/A R0 JOHN J. MCCABE Sept. 15, 1953 c. G.MENARD ET AL MACHINE FOR FINISHING PISTONS 9 Sheets-Sheet 4 Filed Jan.16, 1951 lNV'N TOPS Sept. 15, 1953 c. G. MENARD ETAL MACHINE FORFINISHING PISTONS 9 Sheets-She et 5 Filed Jan. 16, 1951 INVE/V TORSCLIFFORD G. ME/VARD Sept. 15, 1953 c. G. MENARD ETAL MACHINE FORFINISHING PISTONS 9 Sheets-Sheet 6 Filed Jan. 16, 1951 w; 5 a m s m w MG m A x a m gz F w 1 K m v M Aw ,Q

SD w R R 7 0A T E A u e EMA M m r W FNN wa w Sept. 15, 1953 c. s. MENARDETAL MACHINE FOR FINISHING PISTONS 9 SheetsSheet 7 Filed Jan. 16, 1951 AF/G.2.3

INVENTORS CLIFFORD GZMENARD JOHN J. McCAB-E Bra 24+ A 17' YJ'.

Sept. 15, 1953 c. G. MENARD EIAL MACHINE FOR FINISHING PISTONS 9Sheets-Sheet 8 Filed Jan. 16, 1951 //v v5 701?! CL IFFO no a. ME/VARDJOHN'J. u: c455 "OE/ w Patented Sept. 15, 1953 UNITED STATES PATENTOFFECE MACHINE FOR FINISHING PISTONS Application January 16, 1951,Serial No. 206,214

1 3 Claims.

This invention relates to a machine for producing theperipheralsurfaceand also the wrist pin hole in pistons of the typegenerally used in internal combustion engines and particularly to amachine in which these operations are automatically performed on asuccession of piston blanks.

In finish machining the; major periphery or outside surface of a pistonof? this type, it is customary to place the piston in a machine which isequipped to rotate a turning tool about an axis and in contact with. thepiston surface. If a cylindrical surface is desired as in the oldertypes of pistons, the tool rotates around the major axis of the pistonand is alsofed parallel to that axis to generate a finished cylindricalsurface. More recently it has become desirable to form a peripheralsurface which has a slightly elliptical cross section normal to the axisof the piston. This is accomplished by inclining the turning axis of thetool to the axis of the piston and then feeding the tool parallel tovthe piston axis, the tool thereby describing an intersection between twoinclined cylinders when in contact with the piston surface and thereforegenerating an elliptical surface. Such elliptical peripheries areparticularly desirable in the modern, light, cut-away, high speed typeof piston for the purpose of improving the bearing surfaces between thepiston and its cylinder and alsoto provide for expansion of the skirtsof the piston when it is subject to the high temperatures of operation.A- machine for generating an ellipitical periphery is shown anddescribed in the patent to Snader No. 2,121,934.

The interior surface of the parts of a pistons wrist pin hole, the axisof which is disposed generally in a plane at right angles to the axis ofthe peripheral surface of the piston, is customarily finished in aseparate precision boring machine in an operation which is entirelyseparate from that of machining the peripheral surface, these operationsbeing performed in either order. It is extremely important that thewrist pin hole be locatedwith extreme accuracy with respect to, thefinished peripheral surface of the piston. Therefore, in carrying outthe usual successive operations as above described, some means must beprovided to orient the piston, both with respect to theperipheratsurface to. be produced and also with respect, to the finishedwrist pin hole. Thus, the piston must be positioned with respect to somereference surface both in turning. the periphery.- and; in boring thepin hole. This means that h pis on must be Very etc-- curatelypositioned twice, which consumes time and labor. Furthermore, locationby one or more reference surfaces introduces errors dueto. thetolerances of the surfaces, due to variable compression of the surfaces.when the piston: is clamped and due to. chips on the locating surfaces.Time is consumed in locating, orienting, and clamping thepiston foreachoperation, and this time is still greater in, case the hole isboredoff center with respect to the piston axis which has becomecommonpractice. These errorsvary from one piece to another due to tool;wear and also distortion of the piece due to temperature diiferentials.Therefore, even with the most accurate, tedious and time consumingprocedure in orienting the piston first with respect to one machine andthen with respect to the next for the two separate operations, theinaccuracies in the relationship between, the. finished, peripheral.sur--- face and the internal. surface of the-finished wrist pin holecannot, under the customary practice, be controlled within the narrowtolerances,- de sired in the fabrication. of the modern; lightweight,cutaway, high; speed. type ofpistons be-- ing used in present dayautomotive and other internal combustion applications.

It is accordingly the; object of thisinvention, to provide a machine inwhich each of a succession of pistons can be rapidly and accuratelypositioned once, then turned and bored in an automatic cycle in whichthe peripheralv surface and. wrist pin hole formed bear an accuratepredetermined spaced and angular relation to each other and in whichfinished pistons can be replaced by new workpieces, while others arebeing turned and bored.

In the drawings showing; a preferred form of, machine:

Fig. 1 is a general front view of, the machine;

Fig. 2 is a general top plan View;

Fig. 3 is an enlarged View of a portion of Fig. 1, partly in section;

Fig. a is a partial end. View of Fig. 3;

5 is an elevation view of part of the mechanism at the back of themachine in Fig. 2;

Figs. 6 to 1,0 are various views of a workpiece, Fig. 1%) beingschematic to. indicate the elliptical section of the finished peripheralsurface turned. by the machine;

Fig. 11 is an end view partly insection of the work clamping. mechanismalso. shown in: Figs. 1-3, and showing one of the turning tool heads;

Fig. 12 is. a longitudinal view of part of. the

' mechanism of Fig. 11;,

Fig. 13 is a cross-section taken on line i3-|3 of Fig. 12;

Fig. 14 is a face view of a piece included in the mechanism of Figs. 11and 17;

Fig. 14a is an edge view of Fig. 14;

Fig. 15 is an enlargement of part of Fig. 11;

Fig. 16 is a side or longitudinal view of part of the mechanism of Fig.11 showing details of the work clamps;

Fig. 1'7 is an enlarged detailed view of mechanism similar to Fig. 11;

Fig. 18 is a view of part of the mechanism of Fig. 1'7, but taken from adifferent angle;

Fig. 19 is a View showing part of the mechanism of Fig. 17;

Fig. 20 is a face View of a piece shown in Fig. 16;

Fig. 21 is an end view of the clamping mechanism somewhat similar toFigs. 11 and 1'7, also showing the indexing mechanism;

Fig. 22 is a view taken on the lines 2222 of Fig. 21;

Fig. 23 shows details of a plate included in Fig. 21;

Fig. 24 is a schematic drawing of the fluid pressure operating systemand the electrical control system; and

Figs. 25, 26 and 27 are side, top and partial d tailed views of amodified form of turning tool which may be used for turning a taperedperipheral surface on a piston, which surface may also be elliptical.

General The machine illustrated in the general views of Figs. 1 and 2comprises a plurality of circularly arranged pairs of piston clampingmeans which are progressively rotated step by step around an axis andsuccessively presented to a loading position accessible to the operatorand at which finished pairs of work pieces are replaced by new workpieces, and then to present pairs of work pieces first to a pair ofturning tools for turning the peripheral surfaces and then to a pair ofboring tools which bore the wrist pin holes, the latter operations beingperformed simultaneously on successive pairs of pistons while finishedwork pieces are being replaced by new work pieces.

The machine is organized on a T-shaped base it having right and lefthand portions I60, and Hit, respectively, and a rear portion ice.Slidably mounted on a pair of ways ii on the rear portion ific are apair of turning tool heads indicated at !2 for turning the peripheralsurfaces 63 of a pair of pistons 40, Figs. 6-10, these tools beingmounted to feed together on a slide table I8. Mounted on slideways i6and ll on the front portions [9a and Nib of the bed are a pair of boringtool spindles indicated at 25 and 2! arranged to feed toward each otherand to be retracted away from each other and with respect to a pair ofwork pieces 40 in operative position between them.

Referring to Figs. 1-4 and 11-23 mounted in a framework 26 which islocated on the front and central portions of the bed is a piston clampmechanism indicated at 25 comprising a hub 36 which is j ournalledhorizontally to rotate in suitable bearings 32 and 33 in the framework25. Arranged at 120 intervals aroundthe axis of rotation of the hub 39are three pairs of piston clamps 35. one of each pair 35a, 35b and 350being best seen in Figs. 11 and 17. the others being directly behind.These clamps are thus capable of holding and positioning three pair ofpistons til, two pair being in a loading position as illustrated by .4the clamps 35a, two pair being in a turning position as illustrated bythe clamps 35b and the other pair being in a boring position as illustrated by the clamps 350. Therefore, while the operator is replacing afinished pair of pistons by a new pair of work pieces at the loadingposition, another pair in the clamps 35b are in operative position withrespect to the tool heads 12 and are being turned, and a third pair inthe clamps 350 are in operative position with respect to the tool heads20 and 2| and are being bored. After the completion of thesesimultaneous operations, the clamp mechanism is rotated one 120 step,for instance, to place the pistons in the clamps 35a in the turningposition, to place the pistons in the clamps 35b in the boring positionand to return the pistons in the clamps to the loading position so thefinished pieces can be replaced by new workpieces. Means are provided torotate the hub and its assembly progressively clockwise as viewed inFigs. 11, 17 d 21 in 120 steps whereby a succession of raw work piecesmay be fed to the tools and a succession of finished pieces removed atthe loading and unloading stations, and the operation of the turnringand boring tools and the step-by-step rotation of the hub 30 and itsclamping assembly are automatic and in timed relation with each otherand responsive to the loading of the raw Work pieces, as furtherdescribed.

Turning and boring tools Referring to Figs. 1, 2, 11 and 24, the turningtool heads l2 comprise a pair of spindles 58 on the ends of which aremounted tool carrying cups or cages 5i adapted to encompass pistons tilat the turning position and which carry cutting tools 52 mounted ontheir inner surfaces and disposed radially inwardly for engaging theperipheral surfaces of the pistons. The machine is arranged so that thetable [3 upon which the tool heads l2 are mounted moves in and out alongits slideway I l in a direction parallel to the major axes of thepistons 40 when the latter are in turning position represented by theposition of the clamps b.

However, for turning elliptical peripheries as is often preferable inmodern practice, the turning tool spindles 50, i. e. the axes ofrotation of the tools 52 are inclined to the major axes of the pistonsbeing turned and, therefore, to the direction of feed of the tools by anamount which may be of the order of 5 in order to form the desiredperipheral surfaces having elliptical cross sections. The spindles maybe rotatably driven by suitable power means, such as an electric motor53 mounted on the slide l3 driving through pulleys 54 and 55 and belting56, see also Fig. 5. The entire assembly on the table 13 including thetools 52 is fed toward and away from the pistons 40 to engage anddisengage the tools with the work by fluid pressure means including apiston 57 and a cylinder 58 suitably connected between the table 13 andbed I30 and indicated in Fig. 2 1, fluid pressure being supplied throughlines fit and ill to operate the piston 51, as will be d scribed.

It may also be desirable to turn tapered peripheries, either surfaces ofrevolution or elliptical surfaces, and for such purposes a modified formof the turning tool heads is indicated at I 2a in Figs. 25-27, a taperedand elliptical peripheral surface being formed as indicated at 43a in asomewhat exaggerated form for illustrative purposes on a piston 40positioned with respect to a tool head. t2a.. This device; (there-beinga.-pair.

used inthismachine.) comprisesahollow. spindle. tlliljournaled on a.support [3a onavtable. thou the base Hie-and drivenas-through belting,391..

by a motor: 302. On the endat the spindle. 3th.-

399. carries. a. cam portion. 31-2? havinga cam.-sur-- face 3M in.contact with. a cam follower element.

M5. on the tool carrier. 385.. A spring andpushrod. 3% and 3.11. in thecarrier 3&5. serve toforce the cam follower. 315 in .contactwith the.cam sur face. 3-14. Relative movement. of therod 31. 1: to.- the leftrocks the tool holder 395. countercloclr wiseas'viewed in. Fig. 25 thusincreasing. the-diameter. of thecircledescribed. by the toolitfiutoallow turning of the larger portion otthe-taper; relative.movement of the rod- 31a to, the. right allowing. the tool 306th movetowarditsturnings axis under pressure of. the spring 346 toturn thediminished portion. of the taper. As-the turning. tool 522i. is fedtoward the work. to the right, the rod am. is moved relatively to theright to de-- crease the diameter of the periphery toward-the. head ofthe piston lt. For thispurposethe left end of'the rodl3ltrotatesin-thrust. bearings 321% in a bearing. member. 32] connected. bya pivot 322. to. a bell crank 325. pivoted at. 52's having. a camfollower 330. pivoted at. 3.3!. and which may also have. a cam roll3.33..riding on the surface of'a cam. 335' which. is rigid withthe bed Iof the machine. the cam.- follower roll 333 being urged against the camsurface. 334. by a spring. 333. When the toolhead 12a is infullyretracted position, thecam M11633 dropsover a corner. of the cam. 355formed by. the intersection of aback surface 3'4! and the. cam surface334. This rotates the cam follower 330 clockwise so that it. is in theposition shown in.Fig. 25. during:. which. position of the follower 330the camroll 33-3 also. rides in the cam. surface 33.41 during feeding.of. the tool 38% toward the Work. Atthe. end of the: feed of the tooltoward theworhto. the. right, thecam roll 333 drops over acorner 343 ofthe cam. and onto asteeply sloping front surface 3.4.4 which roeizs thecam follower 333icountercloch- Wise into the position. shown in Fig. 27and. in. o

the bell crank'tzli is' allowed'to dropslightly to- O ward the camsurface 334 for any position of the toolhead 12a relative to thecam..33'5and; therefore, the tool 3% is retracted also radially from thework surface during thereturnstroke of. the tool head to. the left. so.thatactual cutting.

ccurs. only. during the. in.-feed-.str.oke. Elie pair. of tool headstZa. are. shown inFigPZG withtheir. axes slightly oftset. to theirdirection; of. feed so. that they turn peripheral, surfaces which. are.elliptical as well astapered.

The boring toolheads- Ztand. 21.,seealso Fig. 3,. comprise. spindles Q.upon which are. mounted suitable boringtools. ti for finishing. thewrist. pin holes it in a pair. of pistons. fifi. in.the'bor ing,p.0sition and rotatably driven. by. suitable power. means, such asel'ectricmotors 62 driving through. pulleys and belting indicated at T3.The-boring 2t. and 2.1. and. their. driving. mechanisms are mounted.respectively on suitable; tables 631 and. =54: to'feed slid'ably toward.and away from An endwise. slidable. rod. 3,191

each.other. on the.slidewaysv I 6: and. I I- to. engage and disengagethe toolsBl. eachwith. a piston 48.

airspace b.etween-.. The assemblies on the tables.

63- and 64iincluding the. tools 61 are moved toward and away from thework. by fluid. pressure means including pistons 65- and'fi'a operatingin cylinders 61 and. 68.. these. assemblies being suit connected-betweenthe tablesfifiand 6:3. and the bed. portions tea. andlllb,.respective1y. Fluid. pressure is supplied. through lines i 33.i855 and i841; M6: to operate the pistons. as. will be de.- scribed.The; tool: heads 26 and 2.! can be. ad.- justably positioned. with.respect. to. their tables 6.3: and tfii-inorder to=position thefinishedwrist pin holes with respect tothe-peripheral surfaces.

. In modern. practice;. these are usually slightly off centerwithrespect to the piston axis, as indicated in Figs; Sand 9.

Clamping mechanism Referring to Figs. 1-3, and 11-24, the clampingmechanism 25. is rotated step by step in increments of 12.0. to. movesuccessive. pairs of. pistons. betweenthe loading position, the turningpositionend-the boring position by fluid pressure mechanism,indicatedatTHLsee particularly Figs.

The'clamping mechanism hub to" is supported in ti e bearings 32'. and.3.3 in the frame by end.

membersBd-andfiiito which it is. bolted, the member 3;; hubtll. being.hollow to accommodate a control. shaft. '15. having a manually operablelever. 16. fixed on. its left. hand. end. as viewed. in.

3. and apair. of'camslfi for raising and lowering the clampmechanismsltd-When the latter are in. the. piston. loading. and? unloadingposition as wilLbe describedindetail.

As. best. viewed. in Figs. 11-13,. the. hub. is triangular incrosssection and'has three fiat faces Eideachhaving. a pair. oftri'angularlyshaped recesses 3|. The hub Bil has a hollow central portion. 8.2. toaccommodate the control shaft Hand connected: by. holes. 813 with eachof. the recesses 85... A..pist.on. clamp. assembly 3.5.i mounted overeachmecessg i ,there being. a pair of piston clampsEton.eachfacedllofthe hub Each clamp assembly. 35;.see Figs. 16-20,comprises. a. fixedbase. portionv 85. bolted. to. the face 8i] of.the-hub 3111 over. an aperture 81.. Slidably fitted. radially of. the.hub Bil in a hole 8? is a. cam follower member 3.8. having a camfollower incontact. with the control shaft to and a collar portion 9}}against which is fitted a clamp lifting member 92 slidably. guided:radially of.

thehub, in the aperture. 81 bya. pin 95. whichis.

fixed to. the hub intheaperture. A plurality of-clamnfingers. 9.5,protruding. above the base 85 are mounted each. on. a stub. shaft 58which is rotatable. in theclamp base and they are adapted toiswingi in.andout. to. grip. apiston. all by one of its ring grooves- 4L. Onthebottom. of. each. of. the. stub, shafts 9:3. is an. integral gear. 99.engagedi by the. toothed. portion. of a relatively rotatable clamp.operating. ring. Hit havinga convenient. handle. 62. for manual rotationrelative to. the. clamp, base 851 The stub. shafts 98f and integralclamp fingers 95 are also slidable lengthwise relative to the clamp base85 by a small amount and each has a lengthwise adjustably positioned pinI04 in contact with a face I05 of the clamp lifting member 92. Eachclamping finger 95 is held yieldingly downward against the liftingmember 92 by a strong spring I01 urging against a collar formed by thegear 99 on the stub shaft 98 at one end and against the base structure85 at the other.

During the progressive rotation of the clamp mechanism 25 around theclamp lifting shaft 15, the cam rolls 89 are in contact with the surfaceof the shaft and the lifting member 92 and lifting fingers 95 are indown or clamping position, but when a clamp 35 is in the loadingposition indicated by the clamp 35a in Figs. 11 and 1'7, the cam roll 89rides up on the lifting cam 11 and forces the lifting member 92, thestubs 98 and the clamping fingers 95 slightly outwardly so that thefingers 95 will clear the shoulder formed by the ring groove 41 of apiston in order more easily to enter the ring groove while the piston 40is being clamped. In the lifted condition of the fingers 95 the clampring IOI can be easily rotated by its handle I02, thereby swinging theclamp fingers 95 in and out of the ring groove 4| of the piston whilethe latter is being loaded and unloaded in the clamping mechanism.

Radially disposed in the center of each clamp 35 is a centering pin Hyieldably slidable inwardly in the clamp base 85 against a spring H2received in a bore H3 in the cam follower member 86, and which isadapted to be received in a hole H5 which has been bored in the centerof the top of the piston 40 for the purpose of centering and positioningthe piston in the clamp mechanism 35, a plurality of positioning lugs 96being also provided on the base for rough positioning of the workpiece.An adjustable pin H6 in the base 85 is also adapted to be received in ahole H1 radially disposed from the hole H5 in the piston head in orderto orient the piston about its axis while it is being positioned in theclamp in order to position the piston 40 with respect to the turning andboring tools so that the finished peripheral surface 43 and wrist pinhole 42 will bear the desired predetermined relation with the piston.

When a piston is being loaded in a clamp at the loading positionrepresented by the clamp 35a, the clamp ring IIlI has been rotated bymeans of its handle I 02 to move the clamp finger 95 rotatably to theiropen position, and the cam roll 09 being in raised position over the cam11, the fingers 95 are also slightly raised with respect to the surfaceI against which the piston bears when it is clamped. A piston may thenbe placed against the surface I20 with its positioning holes H5 and H1over the pins III] and H6, respectively, in which position its axis willbe parallel to the direction of feed of the tools I2 when it comes tothe turning position and normal to the direction of feed of the boringtools 20 when it comes to the boring position. The handle I02 of theclamping ring IOI is then rotated by the operator so as to enter theclamping fingers 95 in an appropriate ring groove 4I of the piston. Theoperator then moves the lever 16 toward him, Figs. 1 and 3, or in acounterclockwise direction as viewed in Figs. 11 and 17, thereby movingthe cam 11 out from under the cam roll 89 and allowing the clamp fingers95 to move downwardly toward the clamp base 85 and pressure operatedcylinder against the shoulder formed on the piston by the ring groove 4|under the force of the springs I01. Additional means are also providedto locate and orient each piston exactly in a clamp at the loadingposition comprising a manually operated locator arm I25 pivotallymounted at I26 on the top of the frame 26 and having a pair of locatorpins I21 adapted to engage in locating holes I28 which have beenpreformed in a pad I29 under the piston 40 and in a line parallel to thewrist pin hole. The locator pins I21 are momentarily entered in theholes I28 while the piston is being positioned in the clamp by downwardmovement of arm I25 after which the arm is allowed to return undertension of a suitable spring I24 to its normal dotted line position asshown in Fig. 11 before the cycle is started.

The cycle is started by pressing a switch as further described, and theclamping mechanism 25 is rotated one step to move the piston from theloading to the turning position after which the operator releases thehandle 16 to return the cam 11 to its normal position under a clamp 35at the loading position, thus raising the fingers on the next successiveclamp so that they can be opened to release and unload a finishedpiston.

It is to be understood that while the mechanism of a single clamp 35 hasbeen described, the description applies to each of three pairs of theclamps 35, each operation, i. e. loading, turning and boring, beingcarried on simultaneously with respect to both of a pair of pistons at atime, six pistons being accommodated at a time.

The operating mechanism 10 for rotating the clamp mechanism 25, bestseen in Figs. 3 and 21-24, comprises a fluid pressure cylinder 539containing a piston I3I connected by a link I32 to a rotatablyreciprocable crank member I 33 having a pawl I35 engageable successivelywith each of three notches I36 in a circular plate I38 which is fast tothe hub 30 of the clamp mechanism 25 through the end member 36 which, inturn, has an integral flange I39 by which it is bolted to the hub 30.Therefore, as viewed in Fig. 21, movement of the piston I3! from left toright causes the pawl I35 to engage a notch I36 and to rotate the plateI36 and clamping mechanism clockwise to index the workpieces, andretraction of the piston to the left repositions the pawl I35 to engagethe next succeedin notch I36 for a successive rotative step. Fluidpressure is controlled and supplied through lines I40 and MI to thecylinder I30 as will be described.

A look finger I45 pivoted at I46 is adapted to be received successivelyin each of three notches I41 spaced at 120 in the periphery of the plateI38 to lock the plate and clamping mechanism in a fixed indexed positionunder the pressure of a plunger I 50 connected to a piston I5! in afluid I52. Pressure is exerted on the right hand side of the piston I5I,as viewed in Fig. 21, to force the plunger I50 against the lock fingerI45 and to keep it in one of the notches I41 when the clamping mechanismis in a given indexed position, but while the clamp mechanism is beingrotated by the piston I 3| the pressure is relieved behind the piston I5I, and a spring I51 retracts it sufiiciently to allow the lock fingerI45 to ride on the periphery of the plate I38 under the yieldablepressure of a plunger I53 and spring I54. Fluid pressure is controlledand fed to the piston I52 through a line I42 in timed relation with therotation of the clamping mechanism as will be further described. The

:9 plunger I50 has a cut -away cam portion I55 engaging a verticallyslidable plungcr I56to operate aeontrol switch duringinwardand outwardmovement o'f'theplunger 150. A cam plate I69 having a cam surfaceportionI6I .is mounted to rotate with the plate I38 to raise a verticallyslidable plungerIGS .whenthepiston 'I3I moves to the right and thus tooperateaswitch 6. Operation of these switches will beiurther described.

Fluid pressure ,system Referring to-Fig.*24,--the turning'tooltable I3is fed inwardly ordownwardly-as shown in'the drawing to engageithetools52"with the work by fluid under pressureiin'aiine IlIl introduced tothe-cylinder 58'"above*thepiston 57, the fluid below the pistonexhausting-through a line IlI. Retraction of thetools'from the workoccurs by a reversal of pressure and exhaust in the 'lines tie and I! I,'an'd'thepistonfl remains in 'a nor- 'mally retracted-positionwithlpressure, in the line I'I i except when't'he tools are being-fedinto the work.

Pressure and'exhaust in the lines "I10 and I?! are controlled by a valveI13 having a plunger Iifil which'is normally. in alleft-hand position,as shown, to allow fiu'idpressure; from a line Elli from any suitablefluid .pressure .source such as a pressure pump '(not. shown) to how tothe line iii to retract the tableand in this position also to allowexhaustfluidfrom the line I19 to flow across the valve and throughasuitable exhaust or return line I16. "When the plunger I'M is moved tothe right, the pressure flow from the line I'le crosses 'thevalve intothe line I10 to feed the table, and e'xhaustfiuidyfrom the line I'IIcrosses the valve an'd'into an exhaust or return line I18, theeXhaustli-ne-I'IS being closed in this condition.

An electric control-system to-be further described includesa-solenoid180 which moves the plunger I'M to the right to-feedtheturnintools on the table I3 into the work and a-solenoid Isl which moves theplunger IN to the left to-retract these tools from the work, thesolenoids being energized sequentially the cycle "of operation atpredetermined points.

The boring tool tables 63 and are fed and retracted with respect totheir work pieces by fluid pressure admitted tothecylinders tl and t8through lines 483 and 1 84., respectively, the fluid ontheoppositesides-ofthe pistons 55 and (it exhausting through'the lines"P85 and I88. 'Pteversal Or -pressure and exhaustin the lines I33 andI85, and IN and 1-86 retractsthe tables 63 and M.

The direction-of flow of fluid pressure in these lines is controlled 'byvalves I90 and I9I having nlungers E92 and 193. "When the plunger IE2 ismoved to the left-in its position, asshown, fluid under pressure from a'suitablesourcethrough a pressure line H5- flows across-thevalve Iiiiiand into the line 'I85-to retract-the-table fit, fluid on -when thelatter are closed, thus also providing 10 valve I91, exceptthat movementof the plunger I93 isin the opposite direction, 1. e. to the left toadmit pressure to the line ISA to feed the table 64 and to the right toadmit pressure to the line I86 to retract the table S 3.

The lines we and I pass through normally open speed control valves I andIdl, respectively, having plungers H93 and I99, each having anextension2il2 and 263. As the boring tool tables 63 and-'64; are fedinto the work, the plunger extensions 'EiEEand'ZGS are contacted by highpoints"2fi5 andZilii of cams 2IIl and ill on the tables 63 and M,respectively, to momentarily close the valves I96 and I91, the valvesbeing momentarily opened during the passage of the low points 2i2 and--2I3 over the plunger extensions to speed up the traverse of the toolsbetween the parts 32a and 42b of the wrist pin holes, see Fig.-8. Whenthe valves I95 and I97 areclosed and the tables 63 and 64 are feedingtoward the work, the fluid exhausting through the lines I 35 and I86passes through check valves 2 I 5 and 2 ii and is'metered through needlevalves lid and 219 which bypass the valves I96 and I91 in the lines I85and I86, respectively, thus providing a rapid traverse feed when thevalves I 96 and It? are open, and a slow valve feed when the valves I95and IQI are closed by the cams 2H3 and 2H while the tools are in contactwith the parts 32m and iib of the workpiece. When the boring tool tables'63 andtt are being retracted from the work by pressure in the lines I55and Hit, the fluid is metered through needle valves 222 and passingthrough check valves 224 and, 225, bypassing the valves I96 and IS? aslow outfeed and a rapid traverse controlled by the cams 2H1 and ill.

The valve plunger I92 is moved to the right to feed the table 63 to thework by a solenoid 253i] and to the left to retract the table by asolenoid 23M, and the plunger I93 is moved to the left to ieedthe tablee4 by a solenoid 23 i and to the right to retract it by a solenoid 235,these solenoids also being energized in timed sequence withthe cycle ofthe machine.

Thedirection of liow of fluid under pressure in the lines Hill and MI tothe cylinder I36 to index-the clamping mechanism 25 in successive stepsis oontrolledby a valve 240 having a plunger 2M which in itsnormal'downward position as shown allows fiuidto flow from a suitablepressure line IlEi acrossthe valve and into the line l ii toretractthepiston I3I to the left ready to index the clampingmechanism.on a successiveoperation; The fluid-exhausting through the line Milcrosses the valve 248 into an exhaust line 243. When theplunger 2 ismoved upwardly, fluid under pressure crosses the valve from the line I75into the line Mil to move the piston Ifil to the right to index theclamping mechanism to anew position, the, fluid exhausting through theline MI and across the valve 2% through a suitable exhaust line 244, theline 2&3 being closed.

When the piston I iBI is in retracted position to the left with pressurein the line MI, pressure is also exerted through the line I52 againstthe piston Ifii inthe cylinder I52 to hold the locking finger I45 inlocked, position in one of the notches I il' 0n the plate I38, theclamping mechanism thereby being held in locked position. When, however,pressureis exerted in the line Hit to index the clamping mechanism, thelines MI and I42 therefore being opened to exhaust, the pressure in thecylinder I52 is released and the piston II is retracted under the forceof the spring I51 to relieve the locking finger I45 so that the clampingmechanism and plate I38 may be indexed to the next operative position.The mechanism is again locked when pressure is shifted to the lines MIand I42 to retract the piston I3I.

The valve plunger MI is moved up to index the clamping mechanism by asolenoid 255 and down to reposition the indexing mechanism by a solenoid25I, energized successively in time with the cycle.

Electric control mechanism The solenoid 250 is first energized to indexthe clamping mechanism by power from a suitable power source line 210which passes through a series of switches I, 2, 3, 5 and 8, see Fig. 24.The switches I, 2 and 3 are closed when all of the tool tables I3, 63and B4 are in fully retracted position, by cams 2', 212 and 213 on thesetables, these switches being otherwise normally open. The normally openswitch 4 is closed when the operator moves the lever toward the front ofthe machine to complete the clamping of the new work pieces as has beendescribed. The switch 5 is closed after the operator releases thelocator arm which carries the positioning pins I2! to position the workas has also been described. The operator then momentarily closes thestarting switch 8 and the solenoid 250 is energized to start the cycle.

The solenoid 25l is then energized to retract the indexing mechanism 10and the solenoids 230, 234 and I85 are then energized to feed all of thetools toward the respective workpieces by power from a suitable sourceline 215, the power to the solenoid 25I flowing directly through aswitch 6, and the power to the tool feed solenoids 230, 234 and I80flowing also through switch i and a line 216.

When the indexing piston I3I moves to the right, the cam surface I6Icloses the switch 5, thus energizing the solenoid 25I and reversing thefluid flow to the cylinder I and starting the piston I3I back to theleft. The cam surface IBI remains in contact with the switch 6 longenough to keep it closed during part of this piston motion to the left.Pressure also being exerted on the piston I5I, the switch operatingplunger I56 is forced out of the cam surface or detent I and raises toclose the switch I, thus completing the circuit to the feed controlsolenoids 230, 234 and I80. All of the tools are fed toward the workunder rapid traverse and slow feed control as previously described, andthe piston I3I having completed its retracting movement, the circuit toall of the previously energized solenoids is broken by the opening ofthe switch 6.

When the turning tool table I3 has completed its infeed cycle, thesolenoid IBI is energized to retract the table by power from a suitablesource line 200 passing through a switch 9, which is closed by a cam 282on the table I3 at the completion of in-feed. In similar fashion, thesolenoids 23I and 235 are energized to retract the tables 63 and 64 bypower from a suitable source line 285 passing through switches I0 and Hwhich are closed by cams 290 and 29I on the tables 63 and 64,respectively. When all of the tool tables are fully retracted, thecircuits are again in condition for the next cycle of operation.

Operation In summary, the operator places a pair of work piece pistons40 in clamps 35a and 351) which are in the loading position. Hepositions them precisely in the clamps by placing them over the locatingpins H0 and IIB, and by operation of the locator arm I25 which placesthe positioning pins I2'I in the positioning holes I28 of the respectivework pieces. He then rotates the clamp mechanism handles I02 which movesthe clamp fingers into the ring grooves 4| of the work pieces. He thencompletes the clamping operation by movement of the clamping lever 16,at the same time releasing and raising the locator arm I25. Whileholding the clamping lever 15 toward him, he then closes the startingswitch 8 and the clamping mechanism 25 is indexed to place the new workpieces in position with respect to the turning tool heads i2 and which,at the same time, returns a pair of finished pieces from the boringstation to the loading station. The indexing mechanism 10, i. e., thepiston I3I returns to retracted position and the turning and boring toolfeed cycle starts and is completed automatically as described above andduring which time the operator may replace the finished pieces by a pairof new pieces at the loading station preparatory to the starting of anew cycle which, of course, can be started as soon as all of the tooltables are again fully retracted.

The number of workpiece clamps and tools may be increased or diminishedwithout departing from the scope of the invention. The machine may alsobe arranged so that the feeding of the tools and their application tothe work is not automatically responsive to the completion of theindexing operation, but responsive to a second manual starting operationsuch as the closing of a switch. Such an arrangement gives the operatormore time to inspect the work just before the tools are applied. Withthe latter arrangement it is, of course, preferable to arrange themachine so that the tools cannot be applied to the work until after theindexing operation is completed, and the clamping mechanism locked inplace.

We claim:

1. A machine for producing a peripheral surface and an internal wristpin hole surface, said surfaces having a predetermined accurate relationto each other in each of a succession of pistons, said machinecomprising work clamping mechanism having a plurality of piston clampsin spaced relation, a turning tool and a boring tool each operable upondifferent successive pistons in said clamps, said clamping mechanismbeing movable step-by-step to index each of said clamps from a clamploading position to said turning and boring tools successively, locatingmeans operable at said loading position for accurately orienting saidpistons in said clamps, said locating means including positioning pinsengageable with preformed holes in said pistons and means preventingmovement of clamping mechanism until after retraction of said locatingmeans.

2. A machine for producing a peripheral surface and an internal wristpin hole surface, said surfaces having a predetermined accurate relationto each other in each of a succession of pistons, said machinecomprising work clamping mechanism having a plurality of piston clampsin spaced relation, a turning tool and a boring tool each operable upondifferent successive pistons in said clamps, said clamping mechanismbeing movable step-by-step to index each of said clamps from a clamploading position to said turning and boring tools successively, means toopen and close said clamps at said loading position to replace saidfinished Work pieces with raw work pieces and means preventing movementof said clamping mechanism when said clamps are open.

3. A machine for producing a peripheral surface and an internal wristpin hole surface, said surfaces having a predetermined accurate relationto each other in each of a plurality of pistons comprising successivegroups of work pieces, said machine comprising Work clamping mechanismhaving a plurality of groups of piston clamps, said groups being inspaced relation, turning tools simultaneously operable on work pieces ineach clamp of a group and boring tools operable simultaneously with theturning tools and with each other upon work pieces in each clamp of adifferent group, operating means to move said clamping mechanismstep-by-step to index each of said groups of clamps successively from aclamp loading position to said turning and boring tools and back again,locating means engageable with said work pieces for accurately orientingsuccessive pistons in said clamps, said operating means beinginoperative except after retraction of said locating means, and meansoperable after each progressive movement of said clamping mechanism toapply said tools to the pistons in successive groups.

CLIFFORD G. MENARD. JOHN J. MCCABE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,434,876 De Fries Nov. 7, 1922 1,453,732 Stevens May 1, 19231,905,094 Hirvonen Apr, 25, 1933 2,121,934 Snader et a1. June 28, 19382,215,369 Gabriel Sept. 17, 1940 2,298,077 Witter Oct. 6, 1942

